Self-shielded CT scanner

ABSTRACT

A CT scanner includes a pair of shields to protect an operator from x-rays from the CT scanner. The CT scanner has a gantry that provides structural support and housing for the components including an x-ray source and a detector arranged on the gantry to face one another. Lead shields are located on opposing sides of the x-ray source and extend between the x-ray source and the detector. The CT scanner further includes a computer located on an opposing side of the gantry from the x-ray source and the detector. The lead shields rotate with the gantry and prevent the x-ray from reaching the operator while the CT scanner is in operation.

This application claims priority to U.S. Provisional Application Ser. No. 60/773,232, filed Feb. 14, 2006.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention made with government support under grant number R44CA107895, awarded by the National Institute of Health (NIH). The government has certain rights in the invention.

BACKGROUND OF THE INVENTION

The present invention relates generally to computer tomography (CT) scanners and more particularly to a compact CT scanner which provides shielding of the operator from the x-rays.

Generally, CT scanners are large enough to scan a patient's entire body. An x-ray source is mounted on a movable ring, which also includes an array of x-ray detectors opposite the x-ray source. The patient lies on a platform that moves through the ring. The ring is rotated so the x-ray source and detectors revolve around the patient taking a series of x-rays, while the patient is moved through the ring on the platform. These scanners are very large because they are capable of scanning an entire body and must include a platform movable through the x-ray source and detectors. An entire room is often dedicated to such a scanner and its associated equipment. To protect the operator from the x-rays the rooms are often lined with leaded material while the operator controls the machine from a computer located outside of the room.

Recently, more compact versions of CT scanners have been provided for scanning a desired portion of a patient's body rather then scanning the entire body. Unfortunately, the operator of the system must still be protected from the x-rays emitting from the CT scanner. Therefore, rooms must still be lined with leaded material, which is expensive.

A CT scanner which protects an operator from the x-rays while providing less expensive and more compact shielding is desirable.

SUMMARY OF THE INVENTION

An example CT scanner according to this invention includes a pair of shields to protect an operator from x-rays of the CT scanner.

The CT scanner includes a gantry that provides structural support and housing for the components including an x-ray source and a detector arranged on the gantry to face one another. Lead shields are located on opposing sides of the x-ray source and extend between the x-ray source and the detector. The CT scanner further includes a computer to control the CT scanner. The computer is located on an opposing side of the gantry from the x-ray source and the detector and faces away from the gantry such that the operator is facing the patient while using the computer.

In operation, the part of the body to be scanned is positioned between the x-ray source and detector. A table for supporting the part of the body to be scanned is small enough to fit between the x-ray source and detector. The lead shields rotate with the gantry and prevent the x-ray from reaching the operator while the CT scanner is in operation. By limiting the area reached by the x-ray the exposure of the operator is limited to an acceptable amount allowing the operator to safely be in the same room as CT scanner when using the computer.

Accordingly, the lead shields of this invention provide sufficient shielding to protect the operator and the room is not required to be lined with lead.

These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a rear perspective view of a self-shielding CT scanner of the present invention;

FIG. 2 is a front perspective view of a self-shielding CT scanner of the present invention;

FIG. 3 is a front perspective view of a self-shielding CT scanner of the present invention;

FIG. 4 is a rear view of a self-shielding CT scanner of the present invention;

FIG. 5 is a side view of a self-shielding CT scanner of the present invention; and

FIG. 6 is a front view of a self-shielding CT scanner of the present invention;

FIG. 7 is a top view of a self-shielding CT scanner of the present invention; and

FIG. 8 is a side view of a self-shielding CT scanner of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 thru 8 illustrate a CT scanner 10 according to the present invention wherein all of the components are contained in a gantry 12. The gantry 12 provides the structural support and housing for the components. The gantry 12 comprises a cross-bar section 14 from which a first arm 16 and a second arm 18 extend perpendicularly from either end, forming a c-shaped assembly.

The first arm 16 houses the x-ray source 20, which in this embodiment is a cone-beam x-ray source 20. The second arm 18 houses a complementary detector 22. The cross-bar section 14 of the gantry 12 houses a motor for rotating the gantry 12 relative to a mounting plate 26. Lead shields 28 are located on opposing sides of the x-ray source 20. The shields 28 extend between the x-ray source 20 and the detector 22. The shields 28 are preferably leaded glass to prevent the patient from feeling closed in during use. The shields 28 may also be leaded plexiglass or some other polymer or other material that does not pass x-rays, but does permit light to pass through. The shields 28 are generally rectangular in shape to enclose the sides of the c-shaped assembly formed by the x-ray source 20, detector 22 and gantry 12.

The CT scanner 10 further includes an on-board computer 30 including a microprocessor or CPU 32, memory 34, a monitor 36 and other hardware and software for performing the functions described herein. The computer 30 controls the rotation of the CT scanner 10, the location and operation of the x-ray source 20 and x-ray detector 22 and collects the data from the detector 22 and stores it for later collection, such as in memory 34. The computer 30 is located on an opposing side of the gantry 12 from the x-ray source 20 and the detector 22. The monitor 36 faces away from the gantry 12 such that the operator is facing the patient while using the computer 30.

In operation, the part of the body to be scanned is positioned between the first arm 16 and the second arm 18 of the gantry 12. A table, or support, 38 (shown in FIG. 8) for supporting the part of the body to be scanned is small enough to fit between the first arm 16 and second arm 18, as well. The table 38 supports the body part to be scanned in order to minimize movement of the patient during the scanning while not interfering with rotation of the gantry 12.

The computer 30 powers on the x-ray source 20. The x-ray source 20 generates a cone-beam x-ray 40 that is directed toward the detector 22. The CPU 32 then controls the motor to perform one complete revolution of the gantry 12, during which time the computer 30 collects multiple images from the detector 22. The images taken by detector 22 are stored in memory 34. Because only a portion of the body is being scanned and the CT scanner 10 gathers more information in each image with the cone-beam x-ray source 20, only a single revolution or less is usually required. The shields 28 prevent the x-ray 40 from reaching the operator while the CT scanner 10 is in operation. The lead shields 28 rotate with the gantry 12. As shown, the x-ray 40 is prevented from extending past the side of the c-shaped assembly. By limiting the area of the x-ray 40 the exposure of the operator to the x-ray is limited to an acceptable amount allowing the operator to safely be in the same room as CT scanner 10 when using the computer 30. Because the shields 28 provide sufficient shielding to protect the operator the room is not required to be lined with lead. As demonstrated above, the CT scanner 10 of the present invention is compact, self-shielded and lower cost than known CT scanners.

Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention. 

1. A computed tomography scanner comprising: a rotatable gantry having opposing sides, wherein the gantry is rotatable about an axis of rotation; an x-ray source mounted to the gantry; an x-ray detector mounted to the gantry opposite the x-ray source; and a shield disposed on each of the opposing sides of the gantry and extending from the x-ray source to the x-ray detector, wherein the shields are fixed relative to the gantry and prevent x-rays from passing through, wherein the shields comprise leaded glass.
 2. The computed tomography scanner of claim 1, further including a computer mounted to the gantry.
 3. The computed tomography scanner of claim 2, including a monitor for the computer that is located on a side of the gantry that is opposite from the x-ray source and the x-ray detector.
 4. The computed tomography scanner according to claim 2, wherein x-rays from the x-ray source are directed away from the computer by the shields.
 5. The computed tomography scanner of claim 1, wherein the x-ray source and the x-ray detector are movable relative to the gantry.
 6. The computer tomography scanner of claim 1, wherein the shields are non-flexible.
 7. The computer tomography scanner of claim 1, wherein the shields are each formed of a single piece of material.
 8. The computed tomography scanner as recited in claim 1, wherein the shields fixed relative to the gantry rotate during rotation of the gantry about the axis of rotation.
 9. The computed tomography scanner as recited in claim 1, wherein the shields are substantially planar.
 10. A computed tomography scanner comprising: a moveable gantry that forms a c-shaped assembly having opposing sides that each define an opening; an x-ray source mounted to the gantry; an x-ray detector mounted to the gantry opposite the x-ray source; and a shield disposed on each of the opposing sides of the gantry and extending from the x-ray source to the x-ray detector, and the shields each have a primarily rectangular shape to close one of the openings.
 11. The computed tomography scanner according to claim 10, wherein the shields comprise leaded glass.
 12. The computed tomography scanner of claim 10, further including a computer mounted to the gantry.
 13. The computed tomography scanner of claim 12, including a monitor for the computer that is located on a side of the gantry that is opposite from the x-ray source and the x-ray detector.
 14. The computed tomography scanner according to claim 12, wherein x-rays from the x-ray source are directed away from the computer by the shields.
 15. The computed tomography scanner of claim 10, wherein the x-ray source and the x-ray detector are movable relative to the gantry.
 16. The computed tomography scanner of claim 10, wherein the shields are fixed relative to the gantry.
 17. The computer tomography scanner of claim 10, wherein the gantry rotates about an axis of rotation.
 18. The computer tomography scanner of claim 10, wherein the shields are each formed of a single piece of material.
 19. A method of directing x-rays of a computed tomography scanner, the method comprising the steps of: a) emitting x-rays from an x-ray source toward an x-ray detector, wherein the x-ray source and the x-ray detector are mounted to opposing sides of a moveable gantry; b) directing the x-rays from the x-ray source away from the opposing sides of the gantry with a shield disposed on each of the opposing sides of the gantry and extending from the x-ray source to the x-ray detector, wherein the shields comprise leaded glass; and c) rotating the gantry about an axis of rotation, wherein the shields are fixed relative to the gantry.
 20. The method of claim 19, wherein said step a) further includes emitting a cone beam x-ray from the x-ray source.
 21. The method to claim 19, wherein said step b) further includes directing the x-rays away from a computer located on a side of the gantry that is opposite from the x-ray source and the x-ray detector.
 22. The method of claim 19, further comprising the step of: d) manipulating a position of the x-ray source and the x-ray detector relative to the gantry with the computer.
 23. The method of claim 22, wherein said step d) further includes shielding an operator from the x-rays with the shields while the operator is using the computer.
 24. The method of claim 19, wherein each of the shields are formed of a single piece of material.
 25. The method of claim 19, wherein the shields are generally rectangular in shape.
 26. The method of claim 19, wherein the shields are non-flexible.
 27. The method as recited in claim 19, wherein said step c) includes rotating the shields fixed relative to the gantry during rotation of the gantry about the axis of rotation.
 28. The method as recited in claim 19, wherein the shields are substantially planar.
 29. A computed tomography scanner comprising: a moveable gantry having opposing sides, wherein the gantry includes a first arm and a second arm to define a c-shaped assembly having the opposing sides which each define an opening; an x-ray source mounted to the gantry, wherein the first arm of the gantry houses the x-ray source; an x-ray detector mounted to the gantry opposite the x-ray source, wherein the second arm of the gantry houses the x-ray detector; and a shield disposed on each of the opposing sides of the gantry and extending from the x-ray source to the x-ray detector, wherein the shields are fixed relative to the gantry and prevent x-rays from passing through, and the shields each have a primarily rectangular shape to close one of the openings. 